Methods of packaging semiconductor devices and structures thereof

ABSTRACT

Methods of packaging semiconductor devices and structures thereof are disclosed. In one embodiment, a method of packaging a semiconductor device includes providing a carrier wafer, providing a plurality of dies, and forming a die cave material over the carrier wafer. A plurality of die caves is formed in the die cave material. At least one of the plurality of dies is placed within each of the plurality of die caves in the die cave material. A plurality of packages is formed, each of the plurality of packages being formed over a respective at least one of the plurality of dies.

BACKGROUND

Semiconductor devices are used in a variety of electronic applications,such as personal computers, cell phones, digital cameras, and otherelectronic equipment, as examples. The semiconductor industry continuesto improve the integration density of various electronic components(e.g., transistors, diodes, resistors, capacitors, etc.) by continualreductions in minimum feature size, which allow more components to beintegrated into a given area. These smaller electronic components alsorequire smaller packages that utilize less area than packages of thepast, in some applications.

One type of smaller packaging for semiconductor devices that has beendeveloped is wafer level packaging (WLPs), in which integrated circuitdie are packaged in packages that typically include a redistributionlayer (RDL) that is used to fan out wiring for contact pads of theintegrated circuit die so that electrical contact can be made on alarger pitch than contact pads of the die. Throughout this description,the term die is used to refer to both the singular and the plural.

When die are positioned on carrier wafers of WLPs and a molding compoundis formed over the die, movement of the die can occur, which isundesirable. Die movement that is often evident as die rotation or dieshifting may cause problems aligning subsequently formed material layersof the WLPs, such as the RDL, particularly in multi-chip packages inwhich two or more die are packaged together in a single package. Suchdie movement in package formation results in reduced yields.

Thus, what are needed in the art are improved packaging designs forsemiconductor devices.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIGS. 1 and 2 show cross-sectional views of a method of packaging asemiconductor device in accordance with an embodiment of the presentdisclosure, wherein a die cave material is formed over a carrier waferand the die cave material is patterned with a plurality of die caves;

FIG. 3A illustrates a top view of the plurality of die caves shown inFIG. 2 for an embodiment wherein dies will be packaged individually inWLPs in accordance with an embodiment;

FIG. 3B illustrates a top view of the plurality of die caves shown inFIG. 2 for an embodiment wherein multiple dies will be packaged insingle WLPs in accordance with another embodiment;

FIGS. 4 through 8 show cross-sectional views of a method of packaging asemiconductor device in accordance with an embodiment, wherein dies areplaced face-up on the carrier wafer;

FIG. 9 shows a more detailed cross-sectional view of a packagedsemiconductor device after singulating the packaged die; and

FIGS. 10 and 11 show cross-sectional views of a method of packaging asemiconductor device in accordance with another embodiment, wherein thedies are placed face-down on the carrier wafer.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the embodiments andare not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the embodiments of the present disclosure arediscussed in detail below. It should be appreciated, however, that thepresent disclosure provides many applicable inventive concepts that canbe embodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the disclosure, and do not limit the scope of the disclosure.

Embodiments of the present disclosure are related to packaging designsand systems for semiconductor devices. Novel packaging methods andstructures will be described herein.

Referring first to FIG. 1, a cross-sectional view of a method ofpackaging a semiconductor device in accordance with an embodiment of thepresent disclosure is shown. A carrier wafer 100 is provided. Thecarrier wafer 100 may comprise glass, silicon, silicon oxide, aluminumoxide, and the like, as examples. The carrier wafer 100 thickness may bebetween about a few mils to several tens of mils and may comprise adiameter of about 300 mm in some embodiments. Alternatively, the carrierwafer 100 may comprise other materials and dimensions.

A layer of adhesive 102 is applied over the carrier wafer 100. Theadhesive 102 may comprise glue and may comprise a liquid when applied,for example. The adhesive 102 comprises a material that is adapted toadhere a plurality of die 108 (not shown in FIG. 1; see FIG. 5) to thecarrier wafer 102 in accordance with embodiments of the presentdisclosure.

A die cave material 104 is formed over the layer of adhesive 102, asshown in FIG. 1. The die cave material 104 is also referred to herein asa photosensitive material or a material in some embodiments. The diecave material 104 may comprise a photosensitive material such as aphotoresist, in some embodiments. The die cave material 104 may comprisea polymer-based material, for example, in other embodiments. The diecave material 104 may comprise a layer of non-photosensitive material,such as polyimide or other materials that is patterned using aphotosensitive material in some embodiments, and then the photosensitivematerial is removed, for example. The die cave material 104 may compriseWLCSP-HD8820, WLCSP-HD8930, or JSR-WPR-5100 having a thickness ofdimension d₁ of about several μm to hundred μm, as examples, althoughalternatively, the die cave material 104 may comprise other materialsand dimensions. The die cave material 104 comprises a material that isacceptable (i.e., regarding properties such as temperature,contamination of other material layers, shrinkage, and elongation) foruse in semiconductor manufacturing and packaging processes, for example.

The die cave material 104 is patterned using lithography with aplurality of die caves 106, as shown in a cross-sectional view in FIG.2. The die cave material 104 may advantageously be patterned directlybecause it comprises a photosensitive material in some embodiments. Thedie cave material 104 may be patterned by exposing the die cave material104 to energy or light through a lithography mask (not shown), and thedie cave material 104 may be developed. Alternatively, the die cavematerial 104 may be directly patterned. Exposed (or unexposed) portionsof the die cave material 104 are then removed, e.g., using an ashprocess, etch process, or a combination thereof, leaving behind thepatterns comprising the die caves 106. The die caves 106 compriseapertures in the die cave material 104 that leave the layer of adhesive102 exposed. Each die cave 106 or pattern may comprise substantially asame size as a size of dies 108 to be placed on the carrier wafer 100 ina top view, for example, as can be seen in FIGS. 3A and 3B.

FIG. 3A illustrates a top view of the plurality of die caves 106 shownin FIG. 2 for an embodiment wherein single dies 108 will be packagedindividually in packages in accordance with an embodiment. FIG. 3Billustrates a top view of a plurality of die caves 106 a, 106 b, and 106c shown in FIG. 2 wherein multiple dies 108 will be packaged in aplurality of single packages in accordance with another embodiment.

FIGS. 4 through 8 show cross-sectional views of a method of packagingthe semiconductor devices 108 (also referred to herein as dies 108 orintegrated circuits 108) in accordance with an embodiment after themanufacturing or packaging step shown in FIG. 2. A plurality of dies 108is placed face-up (e.g., with contact pads 110 exposed) on the carrierwafer 100 in this embodiment, as shown in FIG. 4. Each die 108 comprisesan integrated circuit having electronic circuitry formed thereon, forexample. There may be dozens, hundreds, or thousands of electricaldevices formed on each die 108, for example, depending on theapplication and the size of the dies 108. The dies 108 may comprise oneor more layers of electrical circuitry and/or electronic functionsformed thereon, and may include conductive lines, vias, capacitors,diodes, transistors, resistors, inductors, memory devices, logicdevices, and/or other electrical components, for example (not shown).The dies 108 comprise semiconductor devices or chips that have beenpreviously manufactured on a semiconductor wafer and have beensingulated from the semiconductor wafer, e.g., detached from adjacentdies 108. An automated pick-and-place machine, a portion of which isshown at 111, may be used to attach the dies 108 to the carrier wafer100, e.g., to the layer of adhesive 102 that is exposed through thepatterned die cave material 104.

The dies 108 may include a plurality of contact pads 110 formed at asurface thereof, e.g., on a top surface thereof in the embodiment shownin FIG. 4. The dies 108 are placed face up on the layer of adhesive 102on the carrier wafer 100 within the die caves 106 or patterns in theembodiment shown. Each die 108 is placed within a die cave 106 formed inthe die cave material 104, as shown.

The plurality of dies 108 may comprise the shape of a square orrectangle in a top view, as shown in FIGS. 3A and 3B, which show the diecave 106, 106 a, 106 b, and 106 c patterns. The dies 108 may comprise aplurality of sides 116 in a top view. The dies 108 may comprise foursides, for example, as shown. After the dies 108 are pick-and-placedinto the die caves 106, the die cave material 104 may substantially abut(e.g., be adjacent to) the dies 108 or the integrated circuits on theplurality of sides 116 of the dies 108 in some embodiments.

Next, a molding compound 112 is formed over the dies 108 and the diecave material 104, as shown in FIG. 5. The molding compound 112comprises an encapsulating material and may comprise epoxy resin, silicafiller, and/or positive resist materials, as examples, although othermaterials may also be used for the molding compound 112. The moldingcompound 112 may be deposited or molded onto the dies 108 and die cavematerial 104. The top surface of the molding compound 112 may be higherthan (as shown in FIG. 5), substantially level with (as shown in FIG.6), or slightly lower than, top surfaces of the dies 108. The moldingcompound 112 fills into the gaps between the pluralities of dies 108, asshown.

Placing the plurality of dies 108 on the carrier wafer 100 within thepatterns 106 in the die cave material 104 is advantageous, becausemovement of the plurality of dies 108 on the carrier wafer 100 isprevented or reduced during the deposition of the molding compound 112over the plurality of dies 108. For example, die 108 shift, die 108rotation, and/or die 108 swim is prevented by the use of the novel diecave material 104 comprising the photosensitive material or othermaterials, in accordance with embodiments described herein. The moldingcompound 112 may exert a force 114 outwardly towards edges of thecarrier wafer 100 on the dies 108 during the formation of the moldingcompound 112, for example. Die 108 movement can be more noticeable atedges of a carrier wafer 100 in some packaging processes, yet the noveldie cave material 104 comprising the photosensitive material or othermaterial reduces or eliminates such die 108 movement by retaining thedies 108 in the desired position and locations on the carrier wafer 100within the die caves 106.

Next, an optional grinding process may be performed to planarize the topsurfaces of the plurality of dies 108, so that any unevenness in the topsurfaces of the dies 108 may be at least reduced, and possiblysubstantially eliminated. If the molding compound 112 comprises portionson the top surfaces of the dies 108, these portions of molding compound112 are also removed by the grinding process, as shown in FIG. 6.Accordingly, the top surfaces of the remaining portions of the moldingcompound 112 may be level with top surfaces of the plurality of die 108.Furthermore, the height or thickness of the plurality of dies 108 mayalso be reduced to a desirable height during the grinding process.

A wiring layer comprising an RDL 118 is formed over the top surfaces ofthe plurality of dies 108, also shown in FIG. 6. The RDL 118 maycomprise an insulating material 120 a with a plurality of conductivefeatures 122 formed therein and on a top surface thereof. The conductivefeatures 122 may provide fan-out of contact pads 110 of the dies 108 toother portions of the packaged semiconductor device 130 (see FIGS. 8 and9, for example). Another insulating material 120 b may be formed overinsulating material 120 a and conductive features 122, as shown in FIG.7. Insulating materials 120 a and 120 b of the RDL 118 may comprisepolymers or other insulating materials. Portions of the conductivefeatures 122 of the RDL 118 are coupled to and make electrical contactwith contact pads 110 on the dies 108. Portions of the conductivefeatures 122 may comprise electrical fan-out structures, for example. Anoptional under bump metallization (UBM) structure 124 may be formed onportions of the RDL 118 and insulating layer 120 b, as shown in FIG. 7.A plurality of solder balls 126 is formed over portions of the RDL 118,as shown in FIG. 7. The UBM structure 124 facilitates in the connectionsand formation of the solder balls 126, for example.

The structure shown in FIG. 7 effectively comprises a reconstructedwafer over the carrier wafer 100 that includes the plurality of dies108, for example. The molding compound 112, RDL 118, solder balls 126,and also the die cave material 104 comprise the packages for theplurality of dies 108 which comprises a FO-WLP in the embodiment shown.

Next, at least the carrier wafer 100 is removed from the packagedplurality of dies 108, as shown in FIG. 8. The molding compound 112 andRDL 118 support the dies 108 during the debonding process of the carrierwafer 100 from the packaged dies 108, for example. The layer of adhesive102 may also be removed when the carrier wafer 100 is removed or in aseparate processing step, e.g., using light (i.e., laser) or a thermalprocess. The packaged plurality of dies 108 is then singulated orseparated at singulation lines 128, forming individual packaged dies108, also referred to herein as packaged semiconductor devices 130, asshown in FIG. 9 in a more detailed view. To singulate the packaged dies108 from adjacent packaged die 108, tape (not shown) may be applied tothe dies 108. The tape may comprise dicing tape that supports thepackaged dies 108 during the singulation process. The packaged pluralityof dies 108 is then removed from the tape, leaving the packagedsemiconductor devices 130.

FIG. 9 shows a more detailed cross-sectional view of a packagedsemiconductor device 130 after singulating the packaged dies 108. FIG. 9also shows a more detailed cross-sectional view of a die 108 and the RDL118. The more detailed view of the die 108 and RDL 118 are exemplary;alternatively, the die 108 and RDL 118 may comprise otherconfigurations, layouts and/or designs. In the embodiment shown, the die108 includes a substrate 131 comprising silicon or other semiconductivematerials. Insulating layers 132 a and 132 b may comprise passivationlayers disposed on the substrate 131. Contact pads 110 of the die 108may be formed over conductive features 134 disposed over the substrate131 or disposed in an upper material layer of the substrate 131. Theconductive features 134 may comprise metal and/or semiconductive pads,plugs, vias, or conductive lines that make electrical contact withactive features of the substrate 131, not shown. The contact pads 110may be formed in insulating layers 132 a and/or 132 b that may comprisea polymer layer or other insulating materials.

In the embodiment shown in FIGS. 1, 2, and 4 through 9, the dies 108 areplaced face-up on the carrier wafer 100, with the contact pads 110 ofthe dies 108 facing away from the carrier wafer 100. Note that only onecontact pad 110 is shown for each die 108 in the drawings; however, aplurality of contact pads 110, i.e., dozens or hundreds of contact pads110 may be formed across a surface of each die 108, for example, notshown. A surface of the dies 108 proximate the contact pads 110 isproximate the molding compound 112 in the embodiment of FIGS. 5 through9.

FIGS. 10 and 11 show cross-sectional views of a method of packagingsemiconductor devices or dies 108 in accordance with another embodiment,wherein the dies 108 are placed face-down on the carrier wafer 100. Likenumerals are used for the various elements in FIGS. 10 and 11 that wereused to describe FIGS. 1 through 9, and to avoid repetition, eachreference number shown in FIGS. 10 and 11 is not described again indetail herein.

In this embodiment, a packaged semiconductor device 140 includes a die108 that is placed face-down on the carrier wafer 100, with the contactpads 110 of the die 108 facing towards the carrier wafer 100, as shownin FIG. 10. A surface of the die 108 proximate the contact pads 110 isproximate the die cave material 104 (e.g., the photosensitive material104) in the embodiment of FIGS. 10 and 11. An RDL 118 may be formed thathas conductive features 122 that make electrical contact with thecontact pads 110 of the die 108 in this embodiment, as shown in FIG. 11.

Advantages of embodiments of the disclosure include providing novelpackaging methods and structures that prevent or reduce die 108 shift,die 108 rotation, die 108 swim, and/or other undesired die 108 movementduring the formation of a molding compound 112 and other subsequentprocessing of the packages. The novel packaging methods described hereinare easily implementable in manufacturing and packaging process flowsfor semiconductor devices 108. The packaging methods and structuresachieve higher yields and improved reliability by the use of the noveldie cave material 104 described herein that holds the dies 108 in placein a lateral or horizontal direction concurrently with the layer ofadhesive 102, which holds the dies 108 in place in a vertical direction.Improved results from molding processes are achievable, i.e., of formingthe molding compound 112 of the packages. Connections to subsequentlyformed layers of the packages are made more reliable, such as to the RDL118. Embodiments of the disclosure are particularly beneficial for usein multi-chip packages that have more than one die 108, as shown in thetop view of FIG. 3B, for example, in which die shift can be a concern.

Embodiments of the present disclosure include the methods of packagingsemiconductor devices or dies 108 described herein, and also includepackaged semiconductor devices 130 and 140 that have been packaged usingthe methods and materials described herein.

Although embodiments of the present disclosure have been described withreference to FO-WLPs, a variety of different package types would benefitfrom using a die cave material 104 described herein to assist in theplacement of dies 108 and ensure that the dies 108 remain in placeduring subsequent processing. The novel packaging techniques and diecave material 104 may be implementable in other WLP designs, threedimensional integrated circuit (3DIC) package designs, through-siliconvia (TSV) package designs, bump-on-trace (BOT) packages, or achip-on-wafer assembly packages, as examples.

In accordance with one embodiment of the present disclosure, a method ofpackaging a semiconductor device includes providing a carrier wafer,providing a plurality of dies, and forming a die cave material over thecarrier wafer. A plurality of die caves is formed in the die cavematerial. At least one of the plurality of dies is placed within each ofthe plurality of die caves in the die cave material. A plurality ofpackages is formed, each of the plurality of packages being formed overa respective at least one of the plurality of dies.

In accordance with another embodiment, a method of packaging asemiconductor device includes providing a carrier wafer and forming alayer of adhesive over the carrier wafer. A material is formed over thelayer of adhesive, and the material is patterned with patterns for aplurality of dies to be placed on the carrier wafer. The method includesplacing the plurality of dies on the layer of adhesive over the carrierwafer within the respective patterns in the material, forming packagesover the plurality of dies, and singulating the packages.

In accordance with yet another embodiment, a packaged semiconductordevice includes at least one integrated circuit and a photosensitivematerial disposed around the at least one integrated circuit. Thephotosensitive material substantially abuts the at least one integratedcircuit on a plurality of sides of the at least one integrated circuit.A package is disposed over the at least one integrated circuit and thephotosensitive material.

Although embodiments of the present disclosure and their advantages havebeen described in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the disclosure as defined by the appendedclaims. For example, it will be readily understood by those skilled inthe art that many of the features, functions, processes, and materialsdescribed herein may be varied while remaining within the scope of thepresent disclosure. Moreover, the scope of the present application isnot intended to be limited to the particular embodiments of the process,machine, manufacture, composition of matter, means, methods and stepsdescribed in the specification. As one of ordinary skill in the art willreadily appreciate from the disclosure of the present disclosure,processes, machines, manufacture, compositions of matter, means,methods, or steps, presently existing or later to be developed, thatperform substantially the same function or achieve substantially thesame result as the corresponding embodiments described herein may beutilized according to the present disclosure. Accordingly, the appendedclaims are intended to include within their scope such processes,machines, manufacture, compositions of matter, means, methods, or steps.

What is claimed is:
 1. A method of packaging a semiconductor device, themethod comprising: providing a carrier wafer; providing a plurality ofdies; forming a die cave material over the carrier wafer; forming aplurality of die caves in the die cave material; placing more than oneof the plurality of dies within each of the plurality of die caves inthe die cave material, wherein each die placed within each of theplurality of die caves is attached directly to the carrier wafer;depositing an encapsulating material over the die caves, theencapsulating material adjoining a sidewall of each die placed withineach of the plurality of die caves; planarizing the encapsulatingmaterial, wherein a top surface of the encapsulating material is planarwith a top surface of at least one die placed within each of theplurality of die caves; and forming a plurality of packages, each of theplurality of packages being formed over a respective more than one ofthe plurality of dies.
 2. The method according to claim 1, whereinforming the die cave material comprises forming photosensitive material.3. The method according to claim 1, wherein forming the die cavematerial comprises forming a polymer-based material.
 4. The methodaccording to claim 1, wherein forming the die cave material comprisesforming polyimide.
 5. The method according to claim 1, wherein placingthe at least one of the plurality of dies within each of the pluralityof die caves in the die cave material comprises placing the plurality ofdies on the carrier wafer using an automated pick-and-place machine. 6.The method according to claim 1, further comprising forming a layer ofadhesive over the carrier wafer, before forming the die cave material.7. The method according to claim 1, further comprising removing thecarrier wafer, after forming the plurality of packages.
 8. The methodaccording to claim 1, wherein the encapsulating material comprises oneof epoxy resin, silica filler, or a positive resist material.
 9. Themethod according to claim 1, further comprising forming a redistributionlayer (RDL) over the encapsulating material, conductive portions of theRDL being electrically coupled to at least some of the dies placedwithin each of the plurality of die caves.
 10. A method of packaging asemiconductor device, the method comprising: providing a carrier wafer;forming a layer of adhesive over the carrier wafer; forming a materialover the layer of adhesive; patterning the material with patterns for aplurality of dies to be placed on the carrier wafer; placing theplurality of dies on the layer of adhesive over the carrier wafer withinthe respective patterns in the material, wherein conductive contacts ofthe plurality of dies extend away from the carrier wafer further thanthe material, wherein the respective patterns in the material eachcontain more than one die of the plurality of dies, each one of the morethan one die of the plurality of dies being directly joined to thecarrier wafer; depositing a molding compound over the material, whereina sidewall of one of the plurality of dies faces both the material andthe molding compound; forming packages over the plurality of dies; andsingulating the packages.
 11. The method according to claim 10, whereinforming the packages over the plurality of dies comprises forming onepackage on each of the die.
 12. The method according to claim 10,wherein forming the packages over the plurality of dies comprisesforming one package on a plurality of the dies.
 13. The method accordingto claim 10, wherein placing the plurality of dies comprises placing theplurality of dies face down on the layer of adhesive on the carrierwafer within the patterns in the material.
 14. The method according toclaim 10, wherein placing the plurality of dies comprises placing theplurality of dies face up on the layer of adhesive on the carrier waferwithin the patterns in the material.
 15. The method according to claim10, wherein the plurality of dies comprises contact pads on a surfacethereof, further comprising: forming a redistribution layer (RDL) overthe plurality of dies, wherein forming the RDL comprises coupling aconductive portion of the RDL to contact pads of the plurality of dies;forming a plurality of under bump metallization (UBM) structures overthe RDL; and forming a plurality of solder balls over the plurality ofUBM structures.
 16. The method according to claim 10, wherein formingthe material comprises forming a photoresist.
 17. The method accordingto claim 10, wherein forming the material comprises formingWLCSP-HD8820, WLCSP-HD8930, or JSR-WPR-5100.
 18. The method according toclaim 10, wherein the molding compound comprises one of epoxy resin,silica filler, or a positive resist material.